Ondansetron, a 5HT3 receptor antagonist,first used in 1990,soon became an important drug for nausea and vomiting and more effective than metoclopramide and less sedative than cyclizine. 5HT3 receptors presents on terminals of the vagus nerve and in chemoreceptors trigger zone of area postrema of the brain, 5HT3 receptor antagonist known as setrons . Members of this group are: ondansetron approved in 1991 granisetron approved in 1993 in od dose 10 micrograms/kg tropisetron 1994 od dose 200 micrograms/kg dolasetron 1997 palonosetron approved in 2003 more effective in iv route Indications: radiation induced vomiting in total body irradiation and more dose to the abdomen. 8 mg ondansetron orally before radiation.
chemotherapy-induced vomiting like cisplatin 24 mg ondansetron orally 1 to 2 hrs before chemotherapy. postoperative vomiting. 16 mg ondansetron before the start of surgery.…
